Fired up by a variety of insults, real and imagined, the Giants came to San Francisco for the third time in 11 months and reminded everyone that they’re the defending Super Bowl champions. And that the way they got to the Super Bowl, via Candlestick Park and an NFC championship victory, was no fluke.

“I think it’s a statement game,” said Victor Cruz, who finally got to perform a salsa dance in the Candlestick end zone.

It was quite a statement, the biggest beatdown of the Harbaugh era. The 23-point loss was larger than the combined margin of the 49ers‘ four losses last season: 18 points.

Alex Smith was picked off three times, his first interception hat trick since Dec. 20, 2009; his first multiple-interception game since Oct. 10, 2010. The 49ers’ defense allowed a 100-yard rushing game by an opponent on its home field for the first time in three years. Frank Gore was held to 36 yards rushing. The 49ers team that rolled up 79 points in the previous two games was held to zero trips to the red zone and a mere field goal on the scoreboard.

It was a stunningly lopsided game between teams considered to be evenly matched, ones who were separated by 10 total points in two games last season.

The rematch of the NFC Championship Game had been circled in red from the moment the schedule was released. The 49ers came in 4-1; the Giants were right behind at 3-2.

New York played the disrespect card. Its victories – over Tampa Bay, Carolina and Cleveland – were not impressive. Its losses, to division opponents Dallas and Philadelphia, were considered downright alarming.

“Nobody gives us a chance to win,” Tom Coughlin said before the game, a transparent attempt to fire up his team.

Coughlin got some unexpected assistance in that department from the 49ers’ head coach. While praising defensive end Justin Smith, Gilbride also offered up an opinion that Smith holds a lot, using the colloquialism, “He gets away with murder.”

Harbaugh, always intent on playing the game within the game, pounced. He issued a news release through the team, ripping Gilbride’s “outrageous, irrational statement,” calling it an “incendiary comment.” His timing was specific – the news release came out early Friday afternoon, in plenty of time for the New York media to process it.

Gilbride was shocked when he saw Harbaugh’s reaction.

“I have unbelievable respect for Smith,” Gilbride said. “In a litany of compliments, as laudatory as you could make it, all of a sudden, (Harbaugh) turned it into a negative thing.”

Don’t get him wrong. Gilbride loved the news release.

“That was great,” he said. “Maybe one person would have seen it. Now everyone in the country saw it.”

When asked if it was like feeding red meat to his team, Gilbride smiled.

“Yeah, it worked out,” he said.

Former 49ers center David Baas also smiled at the “red meat” comment.

“We knew what we had to do,” Baas said.

The Giants had to protect Eli Manning, who was batted around like a piñata in January, hit 12 times and sacked six times. They had to establish the run. On defense, they needed to contain the 49ers’ running game and get a lead, forcing the 49ers to play catch-up.

“They want to run. They want to power you,” Giants defensive end Justin Tuck said. “We took that away by getting a lead. That changed the dynamic of the game.”

The Giants’ defense matched the 49ers’ varied offensive packages. The result was Alex Smith’s worst performance in two years.

“I could tell at times we had him rattled,” said Antrel Rolle, who had two interceptions.

Now the 49ers have just four days to process the loss, before Thursday night’s game against Seattle. The Seahawks are also 4-2, having stunned New England on Sunday. The 49ers are in a three-way tie for the NFC West lead. Whatever lessons are to be learned, they need to be absorbed quickly.

“I don’t know that I have the lesson learned right at this moment,” Harbaugh said. “We’ll think through it and see if we can get it corrected.”

Harbaugh is a great coach – no doubt about it. But there’s also no doubt that his tactics, beloved by his team, irritate plenty of NFL people.

So Sunday night, as the NFL scores scrolled across the bottom of the screen, there were probably quite a few nods of approval around the league. The Giants had issued the most important type of statement: the one on the field.